Many components in a jet engine are designed and manufactured to withstand relatively high temperatures. Included among these components are the turbine blades, vanes, and nozzles that make up the turbine engine section of the jet engine. In many instances, various types welding processes are used during the manufacture of the components, and to repair the components following a period of usage. Moreover, various types of welding technologies and techniques may be used to implement these various welding processes. However, one particular type of welding technology that has found increased usage in recent years is laser welding technology.
Laser welding technology uses a high power laser to manufacture parts, components, subassemblies, and assemblies, and to repair or dimensionally restore worn or damaged parts, components, subassemblies, and assemblies. In general, when a laser welding process is employed, laser light of sufficient intensity to form a melt pool is directed onto the surface of a metal work piece, while a filler material, such as powder, wire, or rod, is introduced into the melt pool. Until recently, such laser welding processes have been implemented using laser welding machines. These machines are relatively large, and are configured to run along one or more preprogrammed paths.
Although programmable laser welding machines, such as that described above, are generally reliable, these machines do suffer certain drawbacks. For example, a user may not be able to manipulate the laser light or work piece, as may be needed, during the welding process. This can be problematic for weld processes that involve the repair or manufacture of parts having extensive curvature and/or irregular or random distributed defect areas. Thus, in order to repair or manufacture parts of this type, the Assignee of the present application developed a portable, hand-held laser welding wand. Among other things, this hand-held laser welding wand allows independent and manual manipulation of the laser light, the filler material, and/or the work piece during the welding process. An exemplary embodiment of the hand-held laser welding wand is disclosed in U.S. Pat. No. 6,593,540, which is entitled “Hand Held Powder-Fed Laser Fusion Welding Torch,” and the entirety of which is hereby incorporated by reference.
The hand-held laser welding wand, such as the one described above, provides the capability to perform manual 3-D adaptive laser welding on workpieces of differing types, materials, and configurations. Hence, filler media of various types and forms is supplied to the weld area on a workpiece. In addition, many laser welding processes are conducted in the presence of an inert shield gas. Thus, gas may need to be supplied to the hand-held laser welding wand during some welding processes. Moreover, during operation of the hand-held laser welding wand, the wand may heat up. Thus, a way of cooling the wand may be needed. With conventional laser welding devices, external supplies of gas, coolant, and filler media are coupled to the devices via external conduits, tubing, and/or wiring. Such external systems and supply devices can make the use of the hand-held laser welding wand cumbersome, these systems and supply devices can impair an operator, and/or can interfere with the wand operations.
In response to the above-noted needs, the Assignee of the present application invented a hand-held laser welding wand that can be used to supply various types and forms of filler media to a workpiece via various types of delivery systems, and that can be supplied with gas and/or coolant in a manner that is not cumbersome, does not impair wand operability, and does not interfere with wand operations. This invention is disclosed in U.S. patent application Ser. No. 10/721,632, which is entitled “Hand-Held Laser Welding Wand Having Internal Coolant and Gas Delivery Conduits,” and the entirety of which is hereby incorporated by reference.
Although quite effective in meeting each of the above-stated goals, the inventive wand also evidences certain drawbacks. For example, the wand main body has an optics assembly disposed therein, which is periodically removed for maintenance. In order to remove the optics assembly, the end cap is removed from the main body, which disturbs a cooling water seal that is disposed between the end cap and the main body. Typically, the cooling water seal is a sealant-coated copper gasket. There is an additional cooling water seal of this type between the nozzle and the main body.
The sealant-coated copper gaskets used in the wand are quite effective and robust. However, before reinstalling these seals following optics assembly maintenance, the seals and mating surfaces are thoroughly cleaned and coated with sealant. This operation is preferably conducted in a clean environment, and care is taken to avoid scratching the gaskets and/or mating surfaces. This can be a time consuming process, and can increase overall maintenance costs.
Hence, there is a need for a hand-held laser welding wand that does not rely on removal of a potentially maintenance-intensive coolant seal to remove the optics assembly. The present invention addresses at least this need.